Torque arms have been used to connect a first rotatable body (driven, for example, by a motor) to a second concentric rotatable body (driven by the first rotatable body), both rotating about a common axis of rotation.
However, during the rotation of first and second rotatable bodies, radial distance there between may vary because of component run-outs and/or variations in the axes of rotations of bodies. As is known in the art, component run-out refers to the variation in the radial distance of a given point on an outer surface of a rotating component relative to the axis of rotation, due to, for example, an imbalance of material of the rotating body on one side as compared to the other side, as the component is rotated through a 360° rotation. Torque bars are, therefore, subject to deflection and/or bending due to variations in the radial distance between first and second rotating bodies. Bending and/or deflection of torque bars may result in a misalignment between first and second rotatable bodies. Such misalignment between first and second rotatable bodies renders the positional measurements of an encoder disposed on second rotatable body inaccurate and unreliable.
One example where such a torque bar may be used is a radar system wherein a radar antenna is mounted on a rotatable platform. The rotatable platform is configured to continuously rotate (e.g. via a drive motor assembly) about a central axis through three hundred and sixty degrees of rotation. As is known in the art, such a radar antenna uses an electromechanical connection, which is most often referred to as a slip ring, to transmit electrical signals between a stationary structure (such as a grounding connection) and the rotatable platform, which includes the radar antenna. As is known in the art, a slip ring has a rotatable component generally tracking the rotatable platform and a stationary component in at least electrical communication with the rotatable component. Radar slip rings may further include a position or azimuth encoder to determine the relative angle of the rotatable component (and thereby that of the rotatable platform) with respect to the stationary component of the slip ring and ultimately determine the angular orientation of the rotatable radar antenna.
Under ideal conditions, the rotatable component of the radar slip ring and the rotatable platform would have the same or consistent angular bearing relative to the stationary component of the radar slip ring. A signal generating component of the encoder may, therefore, be mounted on the rotatable component of the slip ring and a reference component of the encoder may be mounted on the stationary component of the slip ring. However, the variations in the axes of rotation of the rotating platform and the rotating component of the slip ring and component run-outs of these rotatable parts may cause undesirable bending and/or deflection of a conventional torque bar connecting the rotatable component of the slip ring and the rotatable platform of the radar, as described above. Such undesirable bending may introduce positional or angular misalignment between the rotating platform and the rotating component of the slip-ring, thereby rendering the positional measurements of the encoder generally unreliable and inaccurate. This, in turn, may adversely affect the performance of the rotatable radar antenna. Alternatives to conventional threaded, rigid torque bars are, therefore, desirable for mitigating these adverse effects on positional accuracy measurements.